Probably the longest and most serious post I will ever write. It's worth reading, though.

A few days ago, I received some terrible news: one of my close friends from school had killed herself. It got me thinking about suicide and depression, and people's attitudes to those who take their own life. Jo wasn't the first person I knew who had done this, and unfortunately I doubt she'll be the last. The inevitability of suicide continuing to be a part of human life is something that I feel needs to be explained, and I hope that this post (which will, I think, mention neither horses nor boats) will shed some light on suicide for those who struggle to understand it.

The first thing to say is this: unless you have been suicidally depressed, you will probably never understand how it feels. It's not like feeling sad, or hopeless, or lonely, or unloved, because although all those things may contribute the sum of the negative feeling is so much more than the component parts. Rather, you become the personification of all that is wrong with the world, and the only way to cleanse the world and to help your friends and family is to remove yourself from life itself. Therefore my first point is this: if you want to understand suicide, you must either have experienced the sincere intention to kill yourself, or you must accept that, whilst you will try to put yourself in someone else's shoes, you will never quite grasp that last little bit. Acknowledging that learning about suicide and truly understanding it are two different things is probably the most crucial step – too many people put their own values on life into the head of someone who, quite clearly, believes something very different, without appreciating that they may as well be expecting a fish to fly.

So, point one: do your best to understand, but realise that without being there yourself you will never fully get it. If you realise that, you will understand more than those who pretend they do understand.

The second point is a difficult one, and it rests on the idea that suicides can be prevented. After someone takes their own life, it is natural for those left behind to feel guilty, frustrated, and angry that they weren't able to prevent it from happening. People feel that they 'should have done more', or that if only they had made themselves more available to the person in question, then that person would have known they could talk about it instead of killing themselves. We feel that because suicide is a deliberate act it is preventable. We feel that if only we had loved the person better (made our love more known) then it would never have happened. It is our fault that the person died.

Suicide has nothing to do with a lack of love (which I will mention again in our third point below). The person who kills themselves does not do so because they are not loved. Although depression robs you of the belief that anyone could love you, it does not necessarily follow that those who commit suicide have done so because they do not feel loved. The simple fact is that all the love in the world cannot stop the progression of an illness as physically and mentally devastating as depression. We never consider ourselves to be guilty causing death through a lack of love if a friend or family member dies of cancer, or in a car crash, or of old age. Some things in life simply take their toll on the body in a way that no amount of love can reverse. Like a tumour, a traumatic accident, or nine decades of a life well-lived, depression is one of those things. People who kill themselves do not die of suicide, they die of depression. Depression is the cause of their death, and suicide is merely the means. Depression is not cured by love (would that it were!) and it is not caused by individuals. Unfortunately, it is a simple truth that loving someone (even with all your heart) has absolutely nothing to do with whether or not they kill themselves. This is because depression completely and utterly robs you of the belief that you are loveable, to the extent that eventually you simply know with all your heart and mind that no-one could ever love you. Note that this is depression causing this belief, not any lack of love from others.

The other idea that argues that suicide is preventable rests on the notion that if you are with someone, day in, day out, twenty-four hours a day, you will prevent them from killing themselves – basically, if you put them on suicide watch and enforce it yourself. It is possible that if there were someone watching that person the entire time then they might find it hard to go through with a suicide. Practically speaking, however, this is rarely an option. Those who commit suicide tend to do so after quite long thought and deliberation. One final thing might be enough to push them over the edge, but rest assured that it will have been in their heads for a long time. Under these circumstances, it's easy to bide your time until you're away from other people. Only stringent 24-hour surveillance for a prolonged period of time (months; years) can prevent a suicide in this sense. This may sound like a fair price to pay, but I believe that it is ethically questionable to impose that kind of sanction on an individual, however sick they are. So, here we go – you can love someone and you can go for a drink with them, give them a big hug at the end and tell them to call you if they feel slightly bad, but that doesn't mean the person won't go home that night and kill themselves. It's not because you haven't tried – it's because humans are autonomous creatures who have the right to make independent decisions.

'I should have noticed' is another cry from those who are recently bereaved. 'I should have noticed something was wrong – why didn't I ask?' Well, usually, people do notice, but the depressed person doesn't want to talk about it (maybe they just would rather ignore it, maybe they think they don't want to bother you with it, maybe they just feel they've got it sorted in their head already). You can't force anyone to tell you how they're feeling or what they're thinking. Also, you cannot expect to predict whether or not your friend or relative is feeling bad – people with depression are experts at hiding how they truly feel, and the day that you think they're beginning to get better could be the day they kill themselves. In fact, it's often the case that having made the decision to bow out of life the depressed person does behave more cheerfully – just as you would on the last day of work before the holidays, when you know that there is an imminent end to the misery.

Point two, then, is this: it is very, very difficult to prevent a suicide. The fact that suicide is (usually) deliberate does not make it preventable.

I said I'd talk more about love, and here we are for point three: the vast majority of people who commit suicide love their friends and family with all their heart, and believe that they are doing the best thing for them. It's often believed not only that friends and family did not love the depressed person enough, but also that the person who kills themselves cannot love those who are being left behind, or else they would not be able to put them through such misery. This is one of those classic occasions when people who have never felt suicidal try to put their own rationalities into those who are suicidally depressed: 'they can't have loved me or they'd never have put me through this pain.' Here's the alternative view...

When you are depressed, the one thing that you can be sure of in life is your own all-encompassing inadequacy as a human being. More than that, you are the thorn in the side of everyday society; you make your friends depressed through your own lack of enthusiasm for life; you upset your family by being unable to function properly; you are a burden on others (at best a worry, at worst a millstone tied around the neck of all those who come into contact with you); everything you touch is contaminated by your own lack of worth; and the only way in which you can improve the situation for everyone else is to remove yourself from it.

When you are depressed, you believe with all your heart (and you know in your head) that you are an awful person. You know that you don't have the right to live. You know that you don't have the right to love. You know that everybody you care about so dearly would be immeasurably better off if only you would just die. You love your family and your friends, and you know that your continued existence is agony for them. You know that the only way to ameliorate this situation is to die.

Suicide, therefore, is an enormous act of love towards others. You kill yourself not because you are giving in, or because you are selfishly thinking of your own needs (although I will touch on this aspect below) – rather, you kill yourself because it is the only way you know of making life better for those people you love the most. Please notice that I have used the verb 'know' rather than 'think'. Obviously, you as someone left behind will argue that this person is wrong, and that killing themselves is the worst thing they can do. However, there is absolutely no doubt in the depressed person's mind that they are doing the right thing for other people. Since there is no doubt about it, there is no other option. You are not worthy of life, but the people whose lives you are ruining are. The only acceptable thing to do is to end your life.

So, point three: suicide is not about selfishly ignoring the love of others, or about not feeling love for others. Suicide is an expression of the love you have for those closest to you. If that sounds warped to you, then that's probably because you're lucky enough never to have felt suicidal.

Next, I'd like to argue that suicide is a personal choice, and that other individuals do not necessarily have a right to expect people to live on through immense distress and illness. If a society can accept that euthanasia is, under certain circumstances, ethically and morally justifiable, then it should be able to accept the same thing of suicide – a person's right to die and their choice to die belong to them and not to others. I personally think that, leaving depression aside, it is very difficult for people who are left behind following a deliberate death, because arguably the deliberate death is most beneficial for the person who has died, and more difficult for those who have to continue their lives. Arguably, it is selfish to leave behind a family and to choose the option-of-no-return of death.

However, if we bear in mind everything I've mentioned above – that you are severely physically and mentally ill; that you do not believe yourself capable of being loved; that you choose this option out of love for others, and so on – then it's a slightly different picture; one in which it becomes selfish to expect the person to continue to live. Let me talk about how it feels to be suicidal, and you might begin to agree that these are acceptable grounds for self-euthanasia.

Suicidal feelings very rarely come out of nowhere. The dramatic image of a jilted or bereaved lover being overcome with emotion and killing themselves is nothing like the general wearing down of depression and the reality of suicide. Before anyone kills themselves, there are usually thoughts of death which have been bothering the person for a long time. At first, suicidal feelings may be scary to the individual experiencing them. Over time, however, they may become mundane, and eventually they are a welcome crutch. Most people start their lives with a healthy dose of self-preservation coursing with the blood through their veins. In some people, however, continuous thoughts of suicide gradually wear down the resistance to death. Death ceases to become something to be avoided at all costs and becomes a viable, attractive alternative to a continued miserable life.

But just how miserable is that life? How bad do things have to be to make suicide a genuinely attractive option?

Depression robs you of everything. It robs you of the ability to stay awake when you need to or to sleep when you want to. It robs you of the ability to spend time with others or to cope on your own. It robs you of your personality and of your memories. It robs you of hope. It robs you of the ability to feel happiness, optimism, gladness, gratefulness, contentedness, a sense of community, or excitement. At the same time, you become so numb that even sadness and despair become mere background distractions against an existence in which nothing can touch you, because you're living a life so isolated from all aspects of the outside world that you cannot even perceive them properly. If you are put on anti-depressants, it is likely that you will start to feel things again, yet in a cruel paradox it is almost certainly the negative emotions that will catch up with you first. If you are feeling suicidal, it is highly likely that the positive feelings have been strangers to you for a long, long time – so much so that you wouldn't even recognise them.

So far, so good – most people accept that depression can do this. But there's more.

When you're really, really depressed, you cease even to be alive in any conventional sense. Here's what I mean: you are unable to hear what people are saying to you even when there is no-one else in the room and you are looking straight at them. You are vaguely aware that they are there and that their mouth is moving, but what is said is a complete mystery to you. Your brain is completely unable to process the sound. It's not even that you don't understand what's being said, as if they were speaking a foreign language or as if you were an animal – it's that any sounds made by the other person do not even reach your consciousness.

You look at things around you and you don't know what you are seeing. You look at a table and you're vaguely aware that it has a function, but if someone handed you a plate of food you'd be as likely to place it underneath the table on the floor, or on a bed, or a windowsill, as you would to place it on the table in between a knife and fork. This leaves you with a sense of utter bewilderment as you look around you at the world, not knowing what it is there for.

People might think you look the same and they might, therefore, expect you to function as normal. You are effectively blind and deaf – how can you respond to them? And since you cannot hear or see, how can you express yourself adequately, in the way that they expect? How can you form words in your head when your mind has simply lost the ability to form words even into thoughts, let alone to translate these thoughts into sound? Have you ever experienced your mind being so utterly numbed (literally, depressed) that you could not even formulate the simplest thought? You will forget to eat, and you will be so hungry that you are in agony, yet you are completely unable to eat because you simply cannot associate that pain in your stomach with hunger, and your mind cannot work out that hunger can be alleviated by eating. You'd think that some instinctive drive would kick in to make you eat, but it's astonishing how much these things rely on language and thought processes.

As this process goes on, you become increasingly isolated. You cannot speak to people or even begin to explain how you feel. You cannot even look at them, because you don't know how to: when a person says, 'look at me', they usually mean 'look in my eyes' – but you forget this; you forget that eyes are meant to meet, so even if you could understand them saying, 'look at me', you would be unable to look in their eyes unless it happened by chance (and believe me, when your head aches with depression, raising your eyes is nigh-on impossible). People give up on you because they don't understand and because they get frustrated by your lack of communication – not all people, although you might wish they would. You get frustrated too, yet you're not sure why – it's only when you're feeling better that you wish you could have told people how much you loved them, how the only emotion you might possibly feel was sheer terror, and how you just wanted to make them happy.

As you become isolated, your mind plays tricks on you. It ceases to get sensory input from its usual sources, so it makes its own (this happened to me, but I have bipolar which complicates the picture anyway). You hear things that aren't happening, but you have no way of distinguishing between what is and isn't real because you can't trust your eyes/ears or your mind. You see things which some remnant of logic in your brain tells you can't be right – 'have wardrobes always been able to walk?' – but you're too tired to do anything about those things that don't really make sense – and anyway, who are you to decide what does and doesn't make sense? Gradually, things start to happen that scare you. You hear screams that come out of nowhere, you hear sinister voices that set your heart racing. You see huge objects flying towards you. You become afraid to leave your room or your house. You become even more isolated. Thoughts come into your head that you shouldn't take your pills. Then...thoughts come into your head that you should take all of them. Fortunately, at this stage, those thoughts still haven't really been translated into words, so you go through the motions of what you've always done, unable to make a decision.

Depression robs you of the capacity to make decisions. How can you make a decision, when you are surrounded by so much that is not real, and when those things that are real cannot be perceived any differently? More importantly, you realise that there is simply no point in making any decisions. Nothing changes. Life stays as awful as it always was. What decision could I make?

You might try to struggle against all this. You might try to work – but you'll find you can't read. The words move on the page, they move around in your head, you read them incorrectly and you give up after five frustrating minutes. You decide to go for a walk, but you're frightened by the world around you and you end up back inside. Life ticks on by as you pretend to everyone else that you're still alright. Life ticks on by, empty but for your increasing sense of desperation mingled with something which can only be described as the most profound feeling of emptiness that it swallows itself up, consumes you, and defines you as empty. You are a void in nature. You are nothing.

And then...if you are nothing...why carry on living? Your mind suddenly seizes on this with unusual clarity. Why am I still living? Am I still living? Should I die? Would that be better? It can't be worse?

And, for the first time in a long time, you find a thought which is articulated clearly; which gives you hope – there is a way out. There is a way to feel like a human again.

This hope now becomes a talisman. It supports you in the dark moments, as you realise that there is another option there. It becomes something to cling on to, and in the better moments (which, surprisingly, are now actually occurring for the first time in months, thanks to the introduction of a get-out clause) it becomes something to mull over more seriously.

Most people who are suicidal think about it a lot before committing the act (or attempting to do so) – often for years. The simple fact is that suicide is an extremely attractive option. There is usually something to push you over the edge. It can be different for different people, but here's an example of what might happen.

You've been having a bad patch. You have everything ready to go, should you need it – a bag of drugs, for example, or perhaps a knife. Maybe you've written a letter, maybe you've made some attempt at a will. It's all there in the background, for now, just biding its time. Maybe you'll never need it – but it's good to be prepared just in case.

Then you have an even worse patch. You look at that bag of pills; at that knife; at that bridge over the motorway; and you think 'if only'. 'Please.' 'One day...'. 'I can't take much more of this.' You know it's final; you know it's a last resort. That's why it's such a fantastic idea.

Finally, something happens – an argument with a friend or spouse (although this can be unlikely – if you're really depressed, arguments tend to be one-sided since you can't really form adequate retorts); a terrible day at work; a horrible story on the news. It's enough. You look at your bed, and you contemplate lying down for another sleepless night, and you realise: 'I can't wake up one more time. I simply can't do it. I can't face waking up, turning off the alarm, and having to face the day. I simply cannot face waking up and realising that I'm still here and that things are still this bad. I cannot face waking up and feeling so utterly, desperately and whole-heartedly sick with myself that I physically vomit. I cannot face that moment where I lie with my eyes closed, hoping against hope that I've died overnight, but knowing that when I open my eyes I will still be here, and none of this nightmare will have ended.' Like those who cannot sleep for fear of a recurring nightmare, you cannot wake up in the knowledge that the illness which has made you a mere shell will continue to haunt you through every second of the day. Waking up is your most feared part of the day. Waking up is your most hated part of the day. Waking up alone makes you want to kill yourself, every single day. You realise that you cannot put yourself through it one more time.

I am now running out of words to explain how it feels. I can't say that you feel really sad, or down, or unhappy. You don't feel any of those things. The point of depression is that you feel nothing, for so long that you cease to be a person – and then, is it really death, if you've already stopped existing? Surely the death happened long ago? Like those who care for elderly relatives with dementia, they know that the person they loved has, in some way, disappeared long before physical death comes round. Depression is the same. True, it may be more reversible than dementia. But people with depression have tried. They've been for a walk, they've eaten healthily, they've tried to sleep at regular hours, they've made time for themselves. They've taken the pills, they've had the electro-convulsive therapy, they've sat through endless sessions of cognitive behavioural therapy, and they've promised time and again that they'll stop self-harming. But these things haven't worked.

Depression is unlike almost any other illness, because it completely robs you of the ability to help yourself. You cannot reach out for help. You do not necessarily want to accept help.

Do you remember how I said that you stop making decisions, and that you stop thinking clearly? That thought 'I want to kill myself' is the first clear thought you will have. The decision, 'I am going to kill myself' is the first (and easiest) decision you will have made in a long while. That is why it feels so good.

Once you've made the decision, you feel something close to a recovery – elation, really. Soon, you will be free! Imagine looking forward to the best holiday of your life. Imagine it was a holiday forever, but not in a way that you would ever get bored of it, or wish you could go home – because actually, home was not your home anymore, and never would be. It had ceased to be home a long time ago. You weren't welcome there, and you didn't know anyone there. You hated it there, because everyone there abused you; called you names; said you were worthless. You realise that you don't ever want to go back there, and then you realise – that place isn't home. Not anymore. You're not going on holiday. You're leaving the worst trip you've ever had, and you're going home – where you're loved, and valuable, and safe. You'll be there forever.

That's how it feels. A bit. Any attempt to put this into words will be inadequate, but hopefully this explains some of it.

So...maybe suicide isn't so selfish. As I've said, most of those who commit suicide will believe whole-heartedly that they're such terrible people that the world (and, most importantly, their families and friends) are better off without them. Equally, they are escaping a world and a life which have just become unbearable. It is very difficult to argue with that.

In this post, I have tried to explain the truth (as I see it) behind some misconceptions about suicide. It leads us here: suicide is not selfish. Suicide is not caused by anyone. Suicide is almost impossible to prevent. Suicide is a positive choice, chosen not as a last resort but as an attractive option. Despair comes into it, but so does hope – suicide is not driven by despair, but by the hope that things will get better if life ends. This is very, very hard to understand if you haven't felt suicidal, but it is true. People see suicide as despair and say how sad it is that the person felt that bad. Yes, it is, but they felt better once they realised how fantastic it would be not to feel terrible all the time.

Finally, there are the religious beliefs. You can believe what you like, but I believe in the salvation of souls – even of those who 'commit' suicide. That gives me, as the person left behind, some comfort. My friend is safe and content at last.